Abstract: The invention relates to a method an computer system for using extrapolation analysis to express an approximate self-consistent solution or a change in a self-consistent solution based on a change in the value of one or more external parameters, said self-consistent solution being used in a model of a system having at least two probes or electrodes, which model is based on an electronic structure calculation comprising a self-consistent determination of an effective one-electron potential energy function and/or an effective one-electron Hamiltonian.